Methionyl Sh-Polypeptide-101: What Is It, Cosmetic Uses, Benefits & Side Effects

Curious about this ingredient? In this article we're explaining exactly what it is and why it's used within cosmetic formulations.
Updated on: July 1, 2025
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We verify all information on this page using publicly available nomenclature standards from The Personal Care Products Council (PCPC), the European Commission's CosIng database and documentation provided directly by ingredient manufacturers. Our analysis is based on technical data from these sources to ensure accuracy and reliability.

What Is Methionyl Sh-Polypeptide-101?

Methionyl Sh-Polypeptide-101 is a lab-designed peptide that starts its life in a stainless-steel fermenter rather than a natural plant or animal source. Scientists build a custom gene that combines the code for the original Sh-Polypeptide-101 with an extra start signal for the amino acid methionine. This new gene is inserted into a safe strain of E. coli, which then acts like a tiny factory, churning out the single-chain peptide. After fermentation the mixture is filtered, purified and dried to yield a fine powder ready for cosmetic use.

The ingredient first caught industry attention when formulators began seeking gentler, more targeted alternatives to animal collagen extracts in the late 1990s. Advances in genetic engineering made it possible to produce consistent, cruelty-free peptides that could mimic or support the skin’s own proteins. Methionyl Sh-Polypeptide-101 quickly entered test formulas, showing promise as a skin-conditioning agent with good stability and a light skin feel.

Today you will most often see it listed on the label of leave-on products such as anti-aging serums, lightweight moisturizers, sheet masks, eye creams and occasional after-sun treatments. Its small molecular size helps it blend well in both water-based and some hybrid emulsions, making it a favorite for formulators aiming for fast absorption without a greasy finish.

Methionyl Sh-Polypeptide-101’s Cosmetic Benefits/Uses

This peptide carries out one key job in skincare: skin conditioning. By binding water to the outer layers of the skin and smoothing surface texture it helps maintain a soft, supple appearance. Regular use can leave the complexion feeling hydrated and looking more even, which is why brands add it to products designed to boost overall skin health.

Who Can Use Methionyl Sh-Polypeptide-101

This peptide is gentle enough for most skin types, including dry, normal, combination and oily skin. Because it is lightweight and non-occlusive it generally will not overwhelm acne-prone or sensitive complexions. There is no known reason it would be unsuitable for mature skin looking for extra conditioning. People with extremely reactive or allergy-prone skin should still read complete ingredient lists to rule out other triggers blended into the final formula.

Methionyl Sh-Polypeptide-101 is produced in a microbial fermenter and contains no animal-derived substances so it fits vegan and vegetarian lifestyles. The manufacturing process also avoids animal testing when brands follow cruelty-free standards.

No specific warnings exist for pregnancy or breastfeeding, but out of caution anyone who is pregnant or nursing should show their healthcare provider the full product label before use. This information is educational only and not medical advice.

The peptide does not increase photosensitivity so it will not make skin more prone to sunburn. Regular daytime sunscreen is still advised as part of a well-rounded routine.

Potential Side Effects/Adverse Reactions

Individual responses to topical Methionyl Sh-Polypeptide-101 can vary. The points below list potential side effects, but most users who apply a properly formulated product will experience none of them.

  • Mild redness or warmth
  • Temporary itching or tingling at the application site
  • Dry patches if the formula also contains strong astringents
  • Rare allergic contact dermatitis in users sensitive to peptides or formulation preservatives
  • Eye irritation if the product accidentally gets into the eyes

If any unwanted reaction occurs stop using the product and consult a healthcare professional.

Comedogenic Rating

Rating: 0 / 5

Methionyl Sh-Polypeptide-101 is a small, water-soluble peptide that does not form a film or leave heavy residues on the skin, so it is highly unlikely to block pores. Its primary role is to condition and hydrate rather than sit on the surface like thicker oils or waxes.

This makes the ingredient suitable for people who are prone to acne or breakouts.

Keep in mind the finished product’s full formula can change how pore-friendly it is, especially if richer butters or silicones are also included.

Summary

Methionyl Sh-Polypeptide-101 is a lab-crafted peptide that conditions skin by attracting water to the outer layers and supporting a smoother surface. Its lightweight nature lets it slip easily into serums, gels and creams where it helps skin feel soft and look more even.

While not a household name, it has a steady following among formulators who want a vegan cruelty-free alternative to animal proteins. Users appreciate the non-greasy finish and gentle profile.

Safety data show a low risk of irritation or pore clogging when used as directed. As with any new skincare product a quick patch test is wise to confirm personal compatibility.

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